Database & Record StructureDefinitionDatabase ComponentsDatabase FieldsFields AttributesData StructureFilesRecordsTreesTablesDialog DatabaseDialog Database StructureLinear FileInverted FileDialog Inverted FileSlide 16Linear File: ExampleSlide 18Slide 19IndexingIndexing ExerciseDemosDatabase & Record Database & Record StructureStructureDania BilalDania BilalIS 530IS 530Fall 2007Fall 2007DefinitionDefinitionA database is a collection of information A database is a collection of information organized in a way that a computer organized in a way that a computer program can quickly retrieve desired program can quickly retrieve desired pieces of data. pieces of data.Database ComponentsDatabase ComponentsFieldsFieldsRecordsRecordsFilesFilesDatabase FieldsDatabase FieldsPieces of information a user can accessPieces of information a user can accessAuthorAuthorTitleTitleJournal nameJournal nameAbstractAbstractDescriptorsDescriptorsOtherOtherFields AttributesFields AttributesNumeric Numeric (e.g., accession number)(e.g., accession number)Textual Textual (e.g., author name)(e.g., author name)Data StructureData StructureA scheme for organizing related pieces of A scheme for organizing related pieces of information. information. Basic types of data structuresBasic types of data structuresFilesFilesRecordsRecordsTreesTreesTablesTablesFilesFilesFileFileA collection of recordsA collection of recordsIn Dialog, a file also refers to a specific In Dialog, a file also refers to a specific databasedatabaseEvery file/database has a number and/or a Every file/database has a number and/or a namenameERIC is a database with a file no. 1 in Dialog.ERIC is a database with a file no. 1 in Dialog.RecordsRecordsRecordRecordA collection of fields which constitutes a A collection of fields which constitutes a complete set of informationcomplete set of informationAuthor, title, journal name, abstract, etc.Author, title, journal name, abstract, etc.A collection of records constitutes a file.A collection of records constitutes a file.TreesTreesData is organized in a hierarchical Data is organized in a hierarchical structurestructureEach element is attached to one or more Each element is attached to one or more elements that is directly beneath it.elements that is directly beneath it.Connections between elements ->branchesConnections between elements ->branchesElements at bottom of a tree with no elements Elements at bottom of a tree with no elements below them -> leavesbelow them -> leavesExample: Yahoo directory. Example: Yahoo directory.TablesTablesData is organized in rows and columnsData is organized in rows and columnsExample: Excel spreadsheetExample: Excel spreadsheetRelational database management systems Relational database management systems store data in the form of related tablesstore data in the form of related tablesAleph system is based on a relational database Aleph system is based on a relational database management system called Oracle.management system called Oracle.Dialog DatabaseDialog DatabaseDocuments or surrogates are stored in a Documents or surrogates are stored in a linear filelinear fileLinear file is transformed into an inverted Linear file is transformed into an inverted filefileDialog Database StructureDialog Database StructureLinear fileLinear fileComposed of document surrogates stored in Composed of document surrogates stored in the IR system in their full, original form.the IR system in their full, original form.Inverted fileInverted fileComposed of all words included in document Composed of all words included in document surrogates excluding stop words.surrogates excluding stop words.Linear FileLinear FileDocuments have to be searched in their Documents have to be searched in their entirety to locate specific information entirety to locate specific information needed.needed.Audiocassette is an analogy to a linear Audiocassette is an analogy to a linear structurestructureSlow and inefficient Slow and inefficientInverted FileInverted FileWords in all documents can be searched Words in all documents can be searched instead of the whole text of the documents instead of the whole text of the documents themselvesthemselvesMusic CD is an analogy to an inverted Music CD is an analogy to an inverted structure.structure.Faster and more efficientFaster and more efficientDialog Inverted FileDialog Inverted FileA list of words in each document surrogate A list of words in each document surrogate is made.is made.Each word is numbered, including phrases Each word is numbered, including phrases and excluding stop words (the, a, an, etc.).and excluding stop words (the, a, an, etc.).Words that are numbered are Words that are numbered are alphabetized (numbers precede letters).alphabetized (numbers precede letters).Dialog Inverted FileDialog Inverted FileAlphabetized entries are followed by the Alphabetized entries are followed by the document number, the field it is from (e.g., document number, the field it is from (e.g., AB, DE), and the number of the entry in AB, DE), and the number of the entry in that field.that field.Linear File: ExampleLinear File: Example101The origins of Don Giovanni.Discusses the history and sources Mozart used in his opera Don Giovanni.DE: Mozart, Opera, Historical Analysis.Inverted FileInverted FileOrigins 101 Ti 2Don 101 Ti 4Giovanni 101 Ti 5Discusses 101 Ab 1History 101 Ab 3Sources 101 Ab 5Mozart 101 Ab 6Used 101 Ab 7…Inverted FileInverted FileMozart 101 DE 1Opera 101 DE 2Historical 101 DE 3Analysis 101 DE 4Historical Analysis 101 DE 3,4IndexingIndexingWords (keywords)Words (keywords)Every important word in a document is Every important word in a document is indexedindexedExample: Information systemsExample: Information systemsIndexed as 2 separate words and as a phraseIndexed as 2 separate words and as a phraseInformation (word)Information (word)Systems (word)Systems (word)Information systems (phrase)Information systems (phrase)Indexing ExerciseIndexing ExerciseIndex a paragraph from Dr. Bilal’s Web Index a paragraph from Dr. Bilal’s Web page (under research and publications)page (under research and publications)Extract the keywords from the first line of Extract the keywords from the first line of the paragraphthe paragraphIndicate the position of each word and the Indicate the position of each word and the field it appears infield it appears inDemosDemosDemo of a Dialog Record